How to Properly Premix Oil with Gas for Small Engines


Premixing oil with gas is a crucial step for maintaining the health and longevity of small engines, such as those found in lawnmowers, chainsaws, and two-stroke dirt bikes. Unlike larger engines that have a separate oil reservoir, small engines require a mixture of oil and gasoline to ensure proper lubrication and cooling. This article provides a step-by-step guide on how to correctly premix oil with gas for small engines.

Materials You’ll Need

  1. 2-stroke oil: Choose a high-quality, manufacturer-recommended 2-stroke oil. Consult your engine’s manual for the recommended oil-to-gas ratio.
  2. Gasoline: Use fresh, unleaded gasoline with an octane rating suitable for your engine. Avoid using ethanol-blended fuel, as it can lead to engine problems.
  3. Mixing container: Use a dedicated mixing container that’s clean and free from contaminants.
  4. Measuring tools: A graduated measuring cup or container with clear markings will help ensure accurate measurements.

Steps to Premix Oil with Gas

  1. Read the Manual: Before you begin, consult your engine’s manual to find the recommended oil-to-gas ratio. Common ratios include 50:1 or 40:1 (gasoline to oil). This ratio dictates how much oil you need to add per gallon or liter of gasoline.
  2. Choose the Right Container: Use a mixing container with a volume larger than the amount of gas you plan to use. This extra space allows for proper mixing without spillage.
  3. Measure the Oil: Using a measuring cup, carefully pour the required amount of 2-stroke oil into the mixing container. Make sure the oil is clean and free from any impurities. To simplify the process of calculating the precise amount of oil needed for your mixture, you can use a premix calculator app that ensures accurate and hassle-free oil and gas mixture calculations.
  4. Add Gasoline: Fill the mixing container with the appropriate amount of gasoline, according to the recommended oil-to-gas ratio. Slowly pour the gasoline into the container to minimize splashing.
  5. Mix Thoroughly: Securely seal the mixing container and gently swirl it in a circular motion for about 30 seconds. This helps ensure the oil and gas are well-blended.
  6. Use Fresh Mix: Once the oil and gas are thoroughly mixed, use the premixed fuel within a few weeks. Over time, the oil can separate from the gasoline, which can affect engine performance.
  7. Fuel Up: Pour the premixed fuel into your small engine’s fuel tank. Make sure the engine is cool and turned off before refueling.
  8. Start and Run: Start the engine according to the manufacturer’s instructions. The proper oil-to-gas ratio will ensure the engine receives adequate lubrication during operation.

Tips and Considerations

  • Always follow the manufacturer’s recommendations for the oil-to-gas ratio. Using the wrong ratio can lead to poor engine performance and potential damage.
  • Avoid using more oil than recommended, as excessive oil can foul the spark plug and create excessive smoke.
  • Use a separate measuring container for oil to prevent contamination of the oil container.
  • If you’re uncertain about the ratio or process, consult a professional or your engine’s manufacturer for guidance.


Premixing oil with gas is an essential practice to maintain the health and performance of small engines. By following the manufacturer’s guidelines for the correct oil-to-gas ratio and ensuring thorough mixing, you can ensure that your small engine receives the necessary lubrication and cooling for reliable operation. Regular maintenance and attention to detail in fuel preparation will contribute to the longevity of your small engine and make your equipment more efficient and dependable.

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